Locking mechanism



sept. 27, 196s Filed Jan. 12, 1965 J. F. PETELLE LOCKING MECHANISM 5 Sheets-Sheet 1 15106771571' James FPeeZZe sept. 27, 196e Filed Jan. 12, 1965 J. F. PETELLE LOCKING MECHANISM 5 Sheets-Sheet 2 Sept. 27, 1966 J. F. PETr-:LLE

LOCKING MECHANISM 5 Sheets-Sheet 5 Filed Jan. l2, 1965 Inveff:

@mes Flpeel le.

United States Patent O 3,275,395 LOCKING MECHANISM James F. Petelle, Chicago, Ill., assignor to Bell & Howell Company, Chicago, Ill., a corporation of Illinois Filed Jan. 12, 1965, Ser. No. 424,962 14 Claims. (Cl. S12- 320) This invention relates to a locking mechanism and more particularly to a locking mechanism which is especially useful in motion picture printers.

It is customary to operate a motion picture printer -continuo-usly at high speed and consequently any stoppage of the printing operation required for replacement of lamps or cleaning of optical elements affects the productive output of the printer. It is also customary to mount printer optical elements to the surfaces of `a drawer assembly member and provide for the removal and insertion of this member in the printer similar, in manner, to` the removal and insertion of a drawer in a cabinet. Removal of this member from the printer leaves an opening through which the printing lamp is readily accessible for replacement purposes.

It is important that accurate optical alignment of the optical elements mounted to the drawer assembly member be attained and maintained upon and `after insertion of this member in the printer. For this purpose it is necessary that the member lbe locked in its mounted position. It is highly desirable that such locking and unlocking operations have the capability of being performed as rapidly as possible in order to keep non-printing time to a minimum.

It is not uncommon for a lm processing laboratory to have extra drawer assembly members on vhand with the optical elements pre-cleaned for immediate insertion in a printer when those already in the printer require cleaning. Such interchangeability between various printers and drawer assembly members requires that any latching mechanism for use therewith have the capability of accommodating variations in thicknesses of the mounting members occasioned by manufacturing tolerances. For the most part, this has been accomplished in the past by using screw fasteners, or where the thicknesses of the mountings do not vary too much, even dog-types of camming devices have `been used. Screw fasteners have the disadvantage that it is often a time consuming process to -put them in place. Moreover, they are frequently positioned at poorly accessible locations.

Accordingly, it is an object of this invention to provide a locking device for locking one member to any one of a number of mounting plates having different thicknesses.

It is another object of this invention to provide a locking device wherein no screws, or other fastening mechanisms having time consuming fastening procedures, are required to hold a locked member rigidly to, land in precise alignment with, a mounting element.

Another disadvantage of the prior art devices is that they require large forces to lock the lens drawer assemblies into place. This not only leads to serious wear problems, but particularly when used with lens drawer assemblies, it also tends to cause distortion of the lens mountings `and lens elements thereby defeating the very purpose for precisely mounting the lenses. This latter problem is especially present with multiple fastening means, such as screw fasteners, wherein one of the -fasteners may be tightened more than another resulting in undesirable structural distortions which impair the operation of the combined mounted and mounting means. Accordingly, it is an object of this invention to provide `a locking device whereby the mounted structure is properly aligned but where very little force is required to attain and maintain that alignment.

A locking mechanism of the type contemplated has a CII 3,275,395 Patented Sept. 27, 1966 mounting member and a member adapted to be locked thereto. According to the principle of the invention a locking element is mounted so that it extends beyond that surface of the member to be locked which is adjacent to the related surface of the mounting member. The mounting surface, such as a plate for example, has a slot therein which receives the locking element and permits it to extend therethrough so as to rest upon the opposite, or locking surface of the mounting plate. A locking slot, also in the mounting plate, intersects with the receiving slot and a similar slot is cut through the related surface of the member to be locked. The locking element is fastened to a locking arm which is pivotally attached to the member lto be locked in a manner so that the locking `arm is movable through an arc within the locking slots. By moving the locking arm through its arc within the locking slots the locking element is moved along the locking surface, urging the member to be locked snugly up against the mounting plate.

Another advantage of this invention is that by using a variable thickness locking element, such as the roller used in the preferred embodiment of the invention described herein, the locking device of the invention can be used with an even wider variety of thicknesses of locking plates. Merely by changing to a roller having a different diameter, an entire new range of mounting plates can be accommodated.

Another advantage of this invention is that by using an over-center element, such as the over-center spring illustrated in the preferred embodiment of the invention, a sufficient amount of force can be exerted on the locking element by means of a relatively small input spring force. In that illustration of the invention a power lever is pivoted about the same point as the locking arm. An overcenter spring is fastened at one end tothe power lever 4and at the other end to the locking arm with the central axis of the spring being somewhat offset from the pivotal axis. In this manner, when the power lever is moved towards the locking arm the central axis of the spring passes over the pivotal axis. That is to say, it breaks over center. When this occurs, the spring forces the power lever and the locking arm towards each other, resulting in motion of the locking element along the locking surface into its locked position. When thusly locked the spring is in its over-center position and its force is at ann. amount sufiicient to hold the mechanism in its locked position.

The foregoing and -other objects, features and advantages of the invention will be more apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a perspective View of a locking device according to the invention, shown in its unlocked position;

FIG. 2 is a perspective view of a locking device according to the invention, shown in its locked positions;

FIG. 3 is a cutaway portion of a side view of a condensing lens drawer for a motion picture printer showing the locking device of FIGS. 1 and 2 embodied therein. This View is taken along the line 3-3 of FIG. 4;

FIG. 4 is a cutaway portion of a top view of a condensing lens drawer for a motion picture printer, taken along the line 4 4 of FIG. 3, showing the locking device .of FIGS. l and 2 embodied therein;

FIG. 5 is a sectional View of the embodiment of the invention shown in FIG. 4, taken along the line 5-5. This view is similar to FIG. 3, but with the condensing lenses and portions of the condensing lens dra-wer removed;

FIG. 6 is a sectional view of the embodiment of the invention shown in FIG. 4, taken along the line 6-6. By placing the section line so as to remove an associated mirror from the lens drawer this View particularly illustrates a means for mounting the condensing lens upon the drawer.

One embodiment of the invention will now be briefly described with reference t-o FIGS. 1 and 2 of the accompanying drawings, wherein like parts bear the same reference numbers in bot-h those and other igures of the drawings. A mounting means 2 has a mounting plate 4 extending therefrom. An inverted L shaped slot is cut through the mounting plate and is comprised of a receiving slot 6 and a locking slot 8. A side wall 10 of a lens drawer has a lens support plate 12 joined to one end thereof by screws 13 (FIG. 5). The lens support plate 12, which serves as the rear portion of the lens drawer, is also the element which is to be physically locked to the mounting plate 4, and has a locking slot (not shown) adjacent to and structurally corresponding with the locking slot 8 of the mounting plate 4.

A locking arm 14, which abuts the under side of the locking slot in plate 12 (not shown) in its raised or unlocked position, is pivotally mounted -about pivot pin 16 which is fastened to the side plate of the lens drawer. At the other end of the locking arm is a roller pin 18 extending substantially perpendicularly outwardly therefrom (see FIG. 4-shown dotted in FIGS. 1 and 2). A roller 20 is rotatably fastened to the pin 1S by an easily removable spring clip 22 (FIG. 3). An extension plate 24 is fastened to the upper portion of the pivoted end of the locking larm 14 by screws 26 and 28. A spring retaining pin is mounted on the forward end of the extension plate'. Also pivotally mounted about pivot pin 16 is a power lever 32. A second and cooperating spring retaining pin 34 is fastened to the power lever as shown in FIG. 2. Extending between the two spring retaining pins 30 and 34 is an over-center tension spring 36.

Having described the -basic structure of a preferred embodiment of the invention the operation of that embodiment will now be described. When it is desired to lock t-he lens support plate 12 to the mounting plate 4 the locking arm is in its raised or unlocked position as shown in FIG. l, wherein the roller 20 is in position to be received by the receiving slot 6. At this time the power lever is in a raised position, as shown, and the overcenter spring is to the right of the pivot pin 16. To position the lens support plate and hence the accompanying structure of the lens drawer (including the lenses which will be described in more detail later) the roller 20 and the locking arm 14 are inserted into the receiving slot and locking slot respectively, as shown in FIG. l.

At the same time an annular step 38 on the lens support plate 12 extends into a circular opening 40 in the mounting plate 4. To assure proper radial alignment of the lens drawer in its mounted position there is a fixed pin 4l extending upwardly from the mating surface of the. mounting plate 4 which enters a slot 42m the lens support plate 12.

To perform the actual locking operation the power lever 32 is pushed downwardly from its FIG. 1 position into the position shown in FIG. 2. During this downward Inotion of the po-wer lever the over-center spring 36 gradually increases in tension until it reaches a maximum when its central axis crosses the axis of the pivot pin 16. Up until this point the spring 36 has tended to urge the locking arm 14 and the power lever 32 into the position shown in FIG. l. 'Ihis :bias force is overcome, however, by the force applied to the power lever during its downward movement. When the over-center spring breaks over center and approaches its FIG. 2 position, the locking arm is forced downwardly and the roller 20 rolls down the rear or locking surface 44 of the mounting plate 4. As the roller moves downwardly the lens support plate is brought snugly and precisely into registration with the mounting plate by the wedging action of the roller against the locking surface of the mounting plate. When the power lever has reached the position of FIG. 2, the angle between the power lever and the locking arm is at a minimum. At this time the force of the over-center spring will also be at a minimum, the roller 20 having rolled down the locking surface a distance that is dictated -by the thickness of the mounting plate 4.

In `order to unlock the lens drawer from the mounting plate it is merely necessary to pull up on the power lever 32 and break the spring over-center in the opposite direction. When this occurs the spring will pull the locking arm upwardly in FIG. 2 while the roller rolls along the locking surface into its position of FIG. 1, at which time the end 46 of the spring retaining pin 34 contacts the under portion of the lens drawer side wall 10 and the upward motion of the power lever 32 is terminated.

Hence, a locking device has -been described which will lock one member to any one of a variety of mounts, each of which has a diiferent thickness. Moreover, this has been accomplished without the use of time-consuming screw fastening means. Rather, the mere depression of a lever brings the locked member into rigid and precise alignment with the mount.

It will be appreciated by those skilled in the art that if it is desired to lock on to an even wider range of mount thicknesses, the rolller 20 can easily be exchanged for Ia different roller size merely by removing the spring clip 22; sliding the roller off of the roller pin 18; replacing the roller; and iinally replacing the spring clip 22.

It will also be appreciated that although an over-center spring has been illustrated in the preferrred embodiment, that other types of similar mechanical devices are adaptable for use with this invention. For example, a toggle mechanism could be employed to apply a great amount of locking force although very little force would be required to operate the toggle mechanism itself. The above described locking mechanism has even greater advantages when used in combination with the lens mounting structure of the motion picture printers lens drawer which will now be described. In FIGS. 3 and 4 a lamp 50 is located within the printer and behind the mounting plate 4 to which the lens drawer is locked. In front of the lamp (going from left to right in FIGS. 3 and 4) is a heat shield 52 fastened to lens mounting devices 54a, 56a, and 5617, .as well as a fourth such device not shown. Condensing lenses 58 and 60 are secured in recesses 62 of the lens mounts. The lens mounts are in turn fastened to the lens support plate 12 by screws 64a, 64b, 66a, and 66b (see also FIG. 6.)

A mirror bracket 66 is fastened to the other side of the lens support plate by screws 66 and 70. A mirror 72 is mounted to the bracket and serves to reflect light beams towards other optics in the printer not shown. The lens support plate has a hole 74 cut therein, as does the heat shield 52 for permitting the light rays from the lamp 50 to go through the condensing lenses towards the mirror 72. The mounting plate 4 has the circular opening 40 therein to accommodate the passage therethrough of the lenses and heat shield as the lens drawer is slid linto position. A cover glass 76 (FIG. 6) is mounted in the hole 74 .and is held in place by a retaining ring 78. The glass 76 prevents dust from entering the lens cabinet through the hole 74.

In operation, the lens `drawer with the lenses, heat shield, mirror, and locking mechanisms attached thereto is slid into position so that the two sets of rollers 20, shown in FIGS. 4 and 6, pass through their respective receiving slots 6, the annular step 38 engages the circular opening 40 in the mounting plate and the slot 42 engages the pin 41. By locking the two locking mechanisms as described above, the condensing lenses are accurately positioned within the motion picture printed and in front of the lamp 50 as shown in FIGS. 3 and 4. The lens drawer may be removed for the purpose of cleaning the lenses or replacing lamp 50 by merely raising lever 32 and sliding the lens drawer out.

If a prior art type of fastening device had been used to position the above described lens mounting drawer the lenses and their mountings would have undoubtedly been distorted fromtheir desired design position. Hence, not only does the invention provide for a rapid means of locking one memberto any one of a variety of mounting plates, each `of which has a different thickness, but it also provides for a distortion free mounting means.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without `departing from the spirit and scope of the invention.

I` claim:

1. In a motion picture printer of the type in which lenses are contained in a drawer slidable within a mounting means, the combination comprising:

a first plate comprising a portion of said drawer;

a second plate comprising -a portion -of said mounting means and having a mating surface adjacent said first plate when said drawer is slid into said mounting means, the other surface of said second plate being a locking surface;

a locking slot in said first plate;

a locking arm having one end thereof pivotally mounted on a side of said drawer and the other end extending through said locking slot in said rst plate;

means for pivoting said locking arm Iabout said pivot;

a locking element mounted on said other end of said locking arm;

a slot in said second plate for receiving said locking element so that said locking element passes therethrough when the drawer is slid into the mounting means the locking arm being of a length so that the locking element is adjacent said locking surface when the drawer is substantially inserted into the mounting means, said second plate being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking element wedges said second plate against said first plate, said drawer thereby vbeing l-ocked to said mounting means; and

means for holding said locking arm and locking element in said locked position.

2. The apparatus of claim 1 wherein said locking element isk comprised of a roller.

3. In a motion picture printer of the type in which lenses are contained in a drawer slidable within a mounting means, the combination comprising:

a first plate comprising a portion of said drawer;

a second plate comprising a portion of said mounting means and having a mating surface adjacent said first plate when said drawer is slid into said mounting means, the other surface of said plate being a locking surface;

a locking slot in said first plate;

a locking arm having one end thereof pivotally mounted on a side of said drawer and the other end extending through said locking slot in said first plate;

means for pivoting said locking arm about said pivot;

a pin extending outwardly from said other end of said locking arm;

a roller detachably and rotatably mounted on said pin;

a slot in said second plate for receiving the roller assembly so that the roller assembly passes therethrough when the drawer is slid into the mounting means, the locking arm being of a length so that the roller is adjacent said locking surface when the drawer is substantially inserted into the mounting means, said second plate being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot,

whereby said roller wedges said second plate against said first plate, said drawer thereby being locked to said mounting means; and

means for holding said locking arm and roller lassembly in said locked position.

4. In a motion picture printer of the type in which lenses are contained in a drawer slidable within a mounting means, the combination comprising:

a rst plate comprising a portion of said drawer;

`a second plate comprising a portion of said mounting means and having a mating surface adjacent said first plate when said drawer is slid into said mounting means, the other surface of said second plate being a locking surface;

a locking slot in said rst plate;

-a locking arm having one end thereof pivotally mounted on a side of said drawer and the other end extending through said locking slot in said first plate;

an over-center device adapted -to pivot said locking arm about said pivot;

means for actuating said over-center device;

a locking means mounted on said other end of said locking arm;

a slot in said second plate yfor receiving said locking means .so that said locking means passes therethrough when the drawer is slid into the mounting means, the locking arm being of a length so that the locking means is adjacent said locking surface when the drawer is substantially inserted into the mounting means, said second plate being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking means wedges said second plate against said first plate, said drawer thereby being locked to said mounting means; and

means for holding said locking arm and locking means in said locked position.

5. The apparatus of claim 4 wherein the locking means is comprised of the rotatably mounted detachable roller.

6. In a motion picture printer of the type in which lenses are contained in a drawer slidable within a mounting means, the combination comprising:

`a first plate comprising a portion of said drawer;

a second plate comprising a portion of said mounting means and having a mating surface adjacent said first plate when said drawer is slid into said mounting means, the other surface of said plate being a locking surface;

a locking slot in said rst plate;

a locking arm having one end thereof pivotally mounted on a side of said drawer and the other end extending through said locking slot in said first plate;

a lever pivotally mounted `adjacent the pivotal end of said locking arm so that the axis of said locking arm and the axis of said lever intersect;

Imeans to rotate said lever with respect to said locking arm;

a spring having one end fastened to the locking arm and the other end fastened to the lever and adapted to have the central axis -thereof cross over the intersection of said locking arm and lever axes when said lever is rotated with respect to said locking arm, thereby forming an over-center spring mechanism;

a locking means mounted on the other end of said locking arm;

a slot in said second plate for receiving said locking means so that said locking means passes therethrough when the drawer is slid into the mounting means, the locking arm being of a length so that the locking means is adjacent said locking surface when the drawer is substantially inserted into the mounting means, said second pla-te being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking means wedges said second plate against said first plate, said drawer thereby being locked to said mounting means; and

means for holding said locking arm and said locking means in said locked position.

7. The apparatus of claim 6 wherein said looking means 4is comprised `of a rotatably mounted detachable roller.

8. In a locking device of the type in which a first plate is brought int-o registration with and looked to a second plate having a mating surface and a locking surface, the combination comprising:

a locking slot in said first plate;

a side plate angularly fastened to said first plate;

a locking larm having one end thereof pivotally mounted on said side plate and the other end extending through said locking slot in said first plate;

means for pivoting said locking arm about said pivot;

a looking element on said other end of said locking arm;

a slot in said second plate for receiving said locking element so that said locking element passes therethrough when said first plate is `brought into registration with said second plate, the lock-ing .arm being of a length so that the locking element is adjacent said locking surface when the rst plate is substantially in registration with said second plate, said second plate Ibeing adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking element wedges said second plate against said first plate; land means for holding said locking arm and locking element in said locking position.

9. The apparatus of claim 8 wherein said locking element is comprised of a roller.

10. In a locking device of the type in which a first plate a locking slot in said first plate;

a side plate a-ngularly fastened to said first plate;

a locking arm having one end thereof pivotally mounted on said side plate and the other end extending through said looking slot in said first plate;

means for pivoting said locking arm about said pivot;

a pin extending outwardly from said other end of said locking arm;

a roller detachably and rotatably mounted on said pin;

a slot in said second plate for receiving said roller assembly so that said roller assembly passes therethrough when said first plate lis brought into registration with said second plate, the locking arm being of a length so that the roller assembly is adjacent to said locking surface when the first plate -is substantially in registration with said second plate, the second plate being adapted to accommodate the motion of said locking arm as it lis pivoted about said pivot, whereby said roller assembly wedges said second plate against said first plate; and

|means for holding said locking arm and said roller assembly in said locked position.

11. In a locking device of the type in which a first plate is brought into registration with and locked to a second plate having a mating surface and a locking surface, the combination comprising:

a locking slot in said first plate;

a side plate angularly fastened to said first plate;

a locking arm having one end thereof pivotally mounted on said side plate and the other end extending through said locking slot in said first plate;

an over-center device adapted to pivot said :locking arm about said pivot;

means for actuating said over-center device;

a locking means mounted on said other end of said locking arm;

a slot in said second plate for receiving lsaid locking means so that said locking means passes therethrough when said first plate is brought into registration with said second plate, the locking arm being of a length so that the locking means is adjacent said locking surface when Ithe first plate is substantially in registration with said second plate, said second plate being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking means wedges said second plate against said first plate; and

mea-ns for holding said locking arm and said locking means in said locked position.

12. The apparatus of Iclaim 11 wherein the locking means is comprised of a rotatably mounted detachable roller.

13. In a locking device of the type in which la first plate is brought into registrati-on with and locked to a second plate having a mating surface and a locking surface, the combination comprising:

a locking slot in said first plate;

a side plate angularly fastened to said first plate;

a lever pivotally mounted adjacent the pivotal end of `said locking arm so that the axis of said locking arm and the axis of said lever intersect;

means to rotate said lever with respect to said locking arm;

a spring having one end fastened to the locking arm and the other end fastened to the lever and adapted to have the central axis thereof cross over the intersection of said locking arm and lever axes when said lever is rotated with respect to said locking arm, thereby forming an over-center 4spring mechanism;

a locking means mounted on the other end of said locking arm;

a slot in said second plate for receiving said locking means so that said locking means pass-es therethrough when said tirst plate is brought into registration with said second plate, the locking arm being of a length so that the locking means is adjacent said locking surface when the first plate is substantially in .registration with said second plate, said second plate being adapted to accommodate the motion of said locking arm as it is pivoted about said pivot, whereby said locking means wedges said second plate against said first plate; and

means for holding the locking arm and ilocking means in said locked position.

14. The apparatus of claim 13 wherein 'said locking means is comprised `of a rotatably mounted detachable roller.

References Cited by the Examiner UNITED STATES PATENTS CLAUDE A. LE ROY, Primary Examiner.

F, DOMO'IOR, Assistant Examiner, 

1. IN A MOTION PICTURE PRINTER OF THE TYPE IN WHICH LENSES ARE CONTAINED IN A DRAWER SLIDABLE WITHIN A MOUNTING MEANS, THE COMBINATION COMPRISING: A FIRST PLATE COMPRISING A PORTION OF SAID DRAWER; A SECOND PLATE COMPRISING A PORTION OF SAID MOUNTING MEANS AND HAVING A MATING SURFACE ADJACENT SAID FIRST PLATE WHEN SAID DRAWER IS SLID INTO SAID MOUNTING MEANS, THE OTHER SURFACE OF SAID SECOND PLATE BEING A LOCKING SURFACE; A LOCKING SLOT IS SAID FIRST PLATE; A LOCKING ARM HAVING ONE END THEREOF PIVOTALLY MOUNTED ON A SIDE OF SAID DRAWER AND THE OTHER END EXTENDING THROUGH SAID LOCKING SLOT IN SAID FIRST PLATE; MEANS FOR PIVOTING SAID LOCKING ARM ABOUT SAID PIVOT; A LOCKING ELEMENT MOUNTED ON SAID OTHER END OF SAID LOCKING ARM; A SLOT IN SAID SECOND PLATE FOR RECEIVING SAID LOCKING ELEMENT SO THAT SAID LOCKING ELEMENT PASSES THERETHROUGH WHEN THE DRAWER IS SLID INTO THE MOUNTING MEANS THE LOCKING ARM BEING OF A LENGTH SO THAT THE LOCKING ELEMENT IS ADJACENT SAID LOCKING SURFACE WHEN THE DRAWER IS SUBSTANTIALLY INSERTED INTO THE MOUNTING MEANS, SAID SECOND PLATE BEING ADAPTED 